Several machines have been developed to attach longitudinal assemblies such as pallets, fencing and lattice-work. Many of these machines feature the use of one or more fastening devices, such as nailing tools and staplers, adapted to repeatedly place a fastener in a given work piece as that work piece is passed by the fastening tool.
One recent improvement in those machines of this type which utilize nailing tools has been an improvement to the tool mounts which attach the nailing tools to the machine frame. Such improvement has been the development of a moveable or "floating" tool mount which allows the tool to accommodate irregularities in the passing work piece by providing for vertical movement of the tool in response to these irregularities. The improved tool mount also allows the nailing tool to swivel slightly in the downstream direction as the nail is being driven. This allows the nailing tool barrel to follow the nail location slightly as the work piece is passed thereby. Together, these two ranges of movement, which are independent of one another, allow for more accurate nail placement and nail depth. Such improvement is described in U.S. Pat. application No. 07/262,884 filed Oct. 26, 1988, by Scott N. Allspaw, entitled "Pallet Building Machine" which has been assigned to the owner of the present application, and is hereby incorporated herein by reference.
One of the other characteristics of the class of machines described above is that they generally consume very large amounts of fasteners due to their relatively high cyclic rate of fastener delivery. It is therefore desirable, if not in fact necessary, to provide relatively large capacity magazines of fasteners to avoid the machine operators having to continuously reload the fastener magazines which would defeat the purpose of automation. It has been found that the use of large coils of fasteners (such as nail belts) provide the best high-volume capacity and ease of delivery.
Because the fastening tool must be allowed to move freely as described above, it is not practical to have such a large fastener magazine attached directly to the tool itself. This is particularly true for the downstream swivel of the tool in the above-described mount, since this movement is in response to the recoil of the tool which could not overcome the heavy lOad Of a large volume magazine. Such a large magazine would therefore completely prevent the swivel movement of the tool and would seriously hinder the tool's movement along the vertical axis.
It is therefore an object of the present invention to provide a fastener magazine capable of containing and dispensing a large volume of fasteners while providing a guide device capable of properly delivering the fasteners to the fastener tool and orienting same for insertion by the tool. Another object of the present invention is to provide such a fastener magazine and guide device which will allow a moveable fastener tool attached to a machine to move freely and without transmitting substantial portions of that movement to the fastener magazine or disrupting the progression of the plurality of ordered fasteners from the feed mechanism of the fastening tool. In this way, the present invention prevents stoppage of the assembly process due to jamming of the fastening tool which can result from misalignment of the ordered fasteners resulting from vibration or accidental interference with the fasteners as they proceed toward the fastening tool. Accomplishing such objectives also prevents substantial vibration from being transmitted to the fastener magazine or to the machine to which it may be attached.
Several fastening tools with fastener magazines are known in the art. These include U.S. Pat. Nos. 3,684,339; 3,707,406; 4,037,771; 4,073,423 and 4,224,731; all of which are incorporated herein by reference.
However, the prior art devices have failed to provide for a fastener magazine and guide device which provides for the use of a high volume fastener magazine with the capability of uniformly and securely dispensing a plurality of fasteners to a moveable fastening tool.
Other advantages of the present invention will be apparent from an appreciation of its full scope in light of the following drawings, description and claims.